Tubular diaphragm valve



Sept. 21, 1965 H. o. SELTSAM 3,207,472

TUBULAR DIAPHRAGM VALVE Filed Jan. 23, 1963 5 Sheets-Sheet 1 INVENTORHAROLD O. SELTSAM ATTORNEYS Sept. 21, 1965 H. o. SELTSAM TUBULARDIAPHRAGM VALVE 5 Sheets-Sheet 2 Filed Jan. 23. 1963 34 FIG. 4

FIG. 5

CLOSED ("ransom INVENTOR. HAROLD O- SELTSAM 3 0 a ay ATTORNEYS Sept. 21,1965 H. o. SELTSAM 3,207,472

TUBULAR DIAPHRAGM VALVE Filed Jan. 23, 1965 5 Sheets-Sheet 4 FIG. IO

(PRIOR ART) I2 I (PRIOR ART) 93' IO&

v q 20' E O 1| 2|.

I r q 23' 98' I6 l4 l3' FIG. ll

0' (PRIOR ART) 9 I I I 28| 90 A I 33' u INVENTOR. l6' HAROLD 0. SELTSAMATTORNEYS Sept. 21, 1965 H. o. SELTSAM TUBULAR DIAPHRAGM VALVESheets-Sheet 5 Filed Jan. 23, 1965 FIG. l3

INVENTION AWMIOZS hm: Emu-m 0 IO 3O 4O 5O 6O I00 SEAT CUP STRAIN (1.)

FIG. I4

0 0 O a o m "(L ZO5ZUPXW ammoni- NUMBER CYCLES TO BREAK INVENTOR. HAROLDO. SELTSAM 705a ay ATTORNEYS United States Patent 3,207,472 TUBULARDIAPHRAGM VALVE Harold 0. Seltsam, Cleveland, Ohio, assignor toTomlinson Industries, Inc., Cleveland, Ohio, a corporation of Ohio FiledJan. 23, 1963, Ser. No. 253,424 18 Claims. (Cl. 251-331) Thisapplication is a continuation-in-part of application Serial No. 217,954filed August 20, 1962.

This invention relates to a novel valve in general and more specificallyis directed to a valve construction embodying a novel sealing means. Theparticular valve here involved and the novel sealing means which formsan integral part of the valve assembly have found a particularlysuccessful application in the liquid food dispensing industry but are byno means restricted to such applications.

For ease of description the sealing means will be referred tohereinafter as a seat cup. The name is a derivative of the structure andfunction of the member as applied to the valve art. The seat cup actsagainst a valve seat and is of a cuplike configuration, which is adistinguishing characteristic.

Seals of this general type are commercially available in various sizesand designs. Among the variety of types that are available, oneparticularly has proved to be of considerable commercial consequence.This type includes a tubular base portion, a coaxial tubular nippleportion of reduced cross-sectional dimension with respect to the baseportion, and a substantially radial transverse shoulder interconnectingthe base and the nipple portion. This assembly forms an upwardly openingchamber, generally resembling that of a cup. The tubular nipple portionterminates in a surface transverse to the axis of the cup, therebyproviding a free end which, as will become apparent hereinafter,provides a portion which is adapted sealingly to co-operate with a valveseat.

When a seat cup of the prior art design is operatively carried in theseal chamber of a valve, the base portion is held against substantialaxial and lateral displacement relative to the valve body in a positionaligned with, but remote from, the valve seat. The nipple portionextends from the base portion toward the valve seat, and at its free endengages the latter to form a fluid-tight seal to control flow. Suitablemeans is employed to mount the nipple removably to the inner end of thereciprocal valve stem, which is aligned with the valve seat. Upon axialmovement of the stern away from the seat, the nipple portion ispartially retracted and, due to the flexure at the transverseshoulderportion, telescopes within the base portion. Such retraction results inbreaking the seal at the valve seat, thereby permitting flow through thevalve. On counter movement of the stem, the sealing engagement betweenthe valve seat and the free end of the nipple portion is re-establishedand flow is thereby terminated.

Over the years, seat cup seals of the foregoing design have establishedan admirable record of performance under rather demanding circumstances;however, one particular problem has been of continual paramount concernto manufacturers. It has been found that over periods of extended use.there is a marked tendency towards failure of the transverse shoulder,and particularly in that zone thereof which joins the tubular baseportion.

One of the main factors influencing failure has been traced to fatigueof the material. Under the existing state of technology, a materialfound most appropriate for use in this application is a siliconeelastomer having a durorneter hardness of from about 30 to about 60points, with a hardness of about 40 to 50 points being preferable. Theparticular elastomer having proved quite satisfactory in all otherrespects, and the durorneter of necessity being within the limitsdefined to maximize effective sealing, a change of material is notindicated. However, any material possessing the essential propertieswould be appropriate in this application. Thus, the elimination, insofaras possible, of fatigue causation is deemed to be the most feasibleapproach to a satisfactory solution to the problem.

The fatigue problem is best described with an example. A wire may bebent or flexed sharply a number of times until the bond between themolecular structure is Weakened, resulting in the separation of thewire. If the flexure is slight, a considerably larger number of cyclesof bending are required before the wire will ultimately fail.

This theory is somewhat applicable to elastomeric materials also. If theflexure or stretching can be kept at a minimum, the useful life of theelastomer can be greatly increased. Moreover, the fatigue life isfurther favorably influenced by an incomplete relaxation of theelastomer, although the theoretical reasons for such are yet unknown.

A further consideration in the fatigue problem of the conventional cupis the excessive stretching at one point in the zone of the transverseshoulder on initial upward movement of the valve stem. The stemmovement, through about the first third of its travel, is not completelylinear, but nutates slightly about a point in the cover of the valveassembly. As a consequence, on opposite diameters in the plane ofmutation, the elastomeric seat cup is stretched and compressed in thezone of the transverse shoulder, resulting in additional uneven flexure.The additional flexure, added to the flexure induced by the telescopingof the nipple into the base portion, serves further to reduce the lifeof the conventional seat cup.

The present design broadly contemplates the general elements definedwith respect to the prior art device in that it contemplates a tubularbase portion and a nipple portion. However, the transverse shoulderportion, in one embodiment of the invention, has been molded toapproximate a sinusoidal shape in cross section, and a portion of thetubular base has been relieved in the zone adjacent the intersection ofthe transverse shoulder portion an amount approximately one-half theaxial distance of the tubular base portion.

The present seat cup in the installed state has an overall axialdimension somewhat shorter than the prior art device. In practice, thisis held to be lesser in axial di- .mension by about one-third of theexpected maximum travel of the valve stem. As expected, when the seatcup is inserted in the valve body, the free end of the nipple portiondoes not rest on the sealing seat until the valve stem is inserted, atwhich time the valve stem flexes the transverse shoulder portiondownwardly about one-third of the overall axial travel of the stem,thereby prefiexing the transverse shoulder. When the valve is opened anamount equal to about one-third of full open, the transverse shoulderportion of the seat cup passes into the unflexed or free state, and whenfull open, the shoulder is flexed only by about two-thirds of the amountof prior art devices.

In practice it has been found that greater control over preflexing theshoulder may be had by proper positioning of the seat cup. Excellentcontrol is achieved by relieving a portion of the bonnet, therebyallowing the tubular base portion to extend slightly into the bonnet. Onassembly the transverse shoulder portion will remain in an upwardposition, thereby insuring the downward flexing of the shoulder oninsertion of the stem and bonnet assembly, without forcing the tubularportion downward also.

The relieved portion in the bonnet serves to improve locating of thetubular portion, preventing cocking, which would result in an imperfectseal. Subsequent adjustment of the. bonnet will have little or no effecton the magnitude of flexure of the transverse wall since the tubularmember extends upwardly in the relieved portion, at all time allowingcontrolled downward flexure of the wall portion when the stem isinserted. As expected, a marked improvement of the preflexed action ishad.

The beneficial results noted could not be achieved by shortening theaxial length of the tubular base portion siince the upper edge of thebase portion would not project above the body portion to form thenecessary fluid tight seal. Proper nipple retraction would be impairedif the length of the tubular portion were reduced, destroying the fineresults heretofore achieved.

The preflexed design coupled with the relieving of the bonnet nut whilerelieving the tubular base portion minimizes shoulder stretching byexercising greater control over flexure regardless of bonnetnutposition. The strain attendant with that degree of stretching whichdoes occur is considerably less than prior art devices, therebyfavorably reducing fatigue. These factors result in materially longerlife of the seat cup with a more uniform sealing pressure beingmaintained. Adjustability of the novel seat cup is available so thatrotation of the cap portion a few turns will adjust the pressure on thefree end portion, thereby accommodating slight variations withintolerances in the length of the stem. The complete operation andremarkable advantages of the invention will be better understood fromthe full description set forth below. I

It is, therefore, an object of this invention to provide a new andimproved valve assembly.

It is a further object .of this invention to provide a novel valveassembly including a novel seat cup sealing member characterized byincreased length of useful life.

It is a further object of this invention to provide, apart from thevalve itself, a novel design for a seat cup sealing member.

It is a still further object of this invention to provide a seat cupsealing member of the type described wherein rolling of the transverseshoulder can be achieved on flexing of such member.

It is a still further object of this invention to provide a novel seatcup sealing member of the type described wherein the magnitude offlexing or strain imposed on the various parts of the member will bematerially less than prior art devices.

It is a still further object of this invention to provide a novel seatcup which is relieved in the proper places so as to be unaffectedadversely by nutations attendant to such valve operation.

- It is a further object of this invention to provide a relieved portionin the bonnet assembly to improve cating the tubular portion of the seatcup on assembly. It is a still further object of this invention toprovide a relieved groove portion in the bonnet to improve the controlover the flexure over a wide variety of adjustments.

It is a still further object to provide a novel valve assembly whichwill minimize strain in the seat cup employed therein.

Other and fuller objects will become readily apparent when reference ismade to the accompanying drawings, wherein:

FIG. 1 is an elevational view of a valve embodying the principles of theinstant invention with parts of the seal chamber and seat cup insection;

FIG. 2 is a front elevational view taken along the line 22 of FIG. 1;

FIG. 3 is a view similar to FIG. 1 with the free end of the seat cupraised off the sealing seat;

FIG. 4 is a fragmentary cross-sectional view of the seat cup;

FIG. 5 is a plan view of the seat cup;

FIG. 6 is an enlarged fragmentary view in section of the seat cup, withphantomlines to illustrate the configuration of the transverse wall inthe open and closed positions;

FIG. 7 is a schematic view of the seat cup;

FIG. 8 is an enlarged fragmentary view of the seat cup inserted in thesealing chamber prior to insertion of the stern in the cap member;

FIG. 9 is an enlarged view similar to FIG. 4 with the cap member placedon the valve body;

FIG. 10 is an elevational view with parts in section of a prior artvalve and seat cup similar in construction to that of FIG. 1;

FIG. 11 is an enlarged elevational view in section of the prior art seatcup of FIG. 10 similar to the conditions of the novel valve assembly ofFIG. 8;

FIG. 12 is an enlarged view of an assembled valve employing a prior artseat cup and showing in phantom lines the position of the transversewall in the open position;

FIG. 13 is a graphical representation showing the relationship of stemtravel versus seat cup strain;

FIG. 14 is a graphical representation of the imposed extension inpercent versus the number of cycles to break;

FIG. 15 is an elevational view of a modified form of bonnet with aportion broken away to illustrate the relief groove; and

FIG. 16 is a fragmentary view in section of the modified bonnet of FIG.15 as itcooperates with the seat cup and body portion.

Referring now to FIG. 1, a valve assembly is illustrated, indicatedgenerally at 10. The valve assembly. 10 comprises a body 11 having anoutlet 12 and an inlet 13. A fluid passageway 14 is provided in thevalve body 11, the former being in communication with outlet and inletportions 12 and 13, respectively.

The passageway 14 comprises a sealing seat 15 which is orientedtransversely of the axis of the outlet 12. Approximately coaxial withthe outlet 12 and joining the seat 15 is a cylindrical portion 16 whichmerges into a frusto-conical portion 17, and thence into an enlargedcylindrical portion 18. The portions 16, 17 and 18 cooperatecollectively to form a seal receiving chamber.

The body is threaded on its outer periphery at its upper extremity 19 toreceive a threaded cap assembly 20.

The cap assembly comprises a bonnet member 21 having a central opening22 slidably to receive a stem means 23. The stem 23 has a collar 24which provides an abutment for a compression spring 25 on one end. Theopposite end of the spring 25 abuts the bonnet member 21 normally tourge the stem toward seat 15. A handle 93 is attached to the stem bysuitable pivot pin means indicated at 24. The handle has an arcuate camportion 25 having a fiat 26 for purposes herein after to be described.

For purposes to be later described, the stem 23 has a knob 27 at itslower extremity, which is joined to the stem by a reduced cylindricalportion 28.

The particular detail of the seat cup and its relationship to the valveis of utmost importance, and will be more specifically described withrespect to FIGS. 4 through 9. As is best seen in FIG. 3, the handle 93,when rotated counterclockwise about its pivotal axis, causes relativesliding between the bonnet 21 and the cam surface 39 such that when theposition as shown in FIG. 3 is reached, the stem reaches its most remoteposition from seat 15. It is obvious upon inspection of FIG. 3 that whenthe handle is released, the spring serves to force the stem in theopposite direction, thereby returning the handle 93 to the verticalposition shown in FIG. 1. It can be appreciated that if the handle 93 isrotated in a clockwise manner so as to bring the flat 26 into engagementwith the bonnet, the valve will remain open, freeing both of the'operators hands. In such cases the stern remains retracted until manualforce is exerted on the handle to unlock the stem and permit the springto close the valve. Thus, it can be seen that the handle can be rotatedso that the valve will automatically close if the cam surface 39 is usedor, in the event continuous flow is desired, the fiat 26 may be utilizedto lock the valve in the open position.

Turning now to FIGS. 4 through 7, the seat cup valve component 30 iscomposed broadly of three major portions: a tubular base portion 31, atubular nipple portion 32 coaxial with the base, and a transverseshoulder portion 33 which joins the base portion to the nipple portion.

More specifically, the tubular base portion comprises a generallycylindrical section 34 of substantial thickness. The outer periphery ofthe base at its free end portion is flared on a slight angle as at 35 toform an external locator ridge for purposes hereinafter to becomeapparent. The cylindrical section 34 is reduced in diameter by afrusto-conical shoulder 43 which merges with a web 36 of about the samethickness as the transverse shoulder portion 33. As seen, the web 36joins the base 31 to the transverse shoulder, the latter being, in crosssection, of general sinusoidal configuration in the illustrated form.

The transverse shoulder portion 33 is joined to the nipple portion 32 bya frusto-conical portion 37 leading into a wall portion of increasedthickness as at 38 which is substantially cylindrical. A transverse endwall closes the nipple portion and provides the same with a free end 40having a lightly chamfered external peripheral surface as shown at 41. Arecess 42 is provided internally of the end wall having a conformationto be removably snap fitted upon the knob 27 and the reduced cylindricalportion 28 of the stem 23. The latter construction provides foreffortless replacement of the seat cup when desired, without thenecessity of replacing the stem assembly as well.

With particular reference to FIGS. 8 and 9, the operation of the seatcup will now be explained. It will be noted that when the cup isinserted in the valve body 13, the base portion 31 engages cylindricalportion 18 with the flared outer periphery 35 acting as a locator meansto limit the degree of insertion. If the seat cup were not mounted onthe cap assembly prior to insertion into the body, and if the transverseshoulder portion were to re main in its free state, the free end 40 ofthe nipple portion 32 would be spaced from the seat 15 a distance equalto d, as seen in FIG. 8. The base portion 31 extends slightly above theupper end of the body 13 as indicated at 45 to provide for axialadjustment of the bonnet, where required to obtain optimum stempositioning relative to seat 15.

The bonnet member 21 has an axially projecting eX- pander which on theouter periphery consists of cylindrical portion 51 and frusto-conicalportion 52 providing a guide surface to center the cap with respect tothe valve body and seat cup 30. In assembling the cap assembly 20 to thebody portion 13, the stem is inserted with the knob 27 in the recessedportion 44, the fit being a snaplike action, since the cylindricalportion 42 must necessarily be expanded to allow the knob 27 to passtherethrough. The frusto-conical surface 52 on the axial extension 50guides the cap member so as to align it concentrically with the bodyportion 13 and the seat cup 30. Additionally, the expander 50co-operates with the cylindrical surface 18 of the passageway 14 toexpand and grip the base portion 31 of the seat cup, as will bedescribed with greater particularity.

A modified form of bonnet 121 is shown in FIG. 15 having an axiallyextending expander 150. The expander is provided with an outercylindrical portion 151 which extends from the axially opening groove inthe bonnet to a converging frusto-conical portion 152 for purposeshereinafter noted.

The parts in the assembled position are shown fragmentarily in theenlarged view of FIG. 9. The respective diameter of the surface 51 issomewhat greater than the internal peripheral surface of the cylindricalportion 34, so that the base portion is compressed between the axialextension 50 and the surface 18 of body 13 to establish a sealingrelationship between the base portion and the surface 18. As can beseen, where the parts of the cap assembly 20 are assembled with the bodyportion, the transverse shoulder portion 33, generally sinusoidal in thefree state, is flexed to assume the more nearly flattened configurationshown at 55. This configuration results from the stem forcing the nippleportion away from the bonnet While the base portion 34 is maintainedagainst substantial axial movement. The free state configuration andposition is shown in phantom at 56 and the configuration of thetransverse portion is shown in phantom at 57 when the valve is raised tofull open, the handle at such time being in the position shown inphantom lines at 58.

Referring now to FIG. 16, the co-operative relationship of the valvebody 11, the seat cup 30, and the modified form of bonnet 121 will beexplained. When the parts are assembled, as shown in FIG. 8, the tubularbase portion 34 extends above the body slightly. When the bonnet 21 isbrought into position, as shown in FIG. 9, the tubular portion is forceddownwardly a slight amount. The modified form of bonnet illustrated inFIG. 16 allows the tubular base portion 34 to remain extended above thebody even when the bonnet 121 is tightly drawn to the body 11 as shown.The tubular base portion overlaps the intersection of the two partsinsuring a fluid tight seal. Assistance in locating is given by theguiding portion 152 spreading the tubular portion slightly as the bonnetis rotated, until finally gripped between the eX- tended cylindricalportion 150 and the outer wall 161 of the groove 160, both being oflesser radial dimension than the tubular base portion. The outer wall161 of the groove 160 is substantially coextensive with the wall 18 ofthe body 11. In addition to precluding the possibility of cocking of thetubular base portion in the body on assembly, the relieved bonnetconstruction allows greater control to be exercised over the amount offlexing of the transverse shoulder, and a wider range of adjustabilityof the bonnet. Moreover, it insures against the tubular portion beingforced downwardly into contact with the frustoconical portion 17 of thebody 11 which could impair the smooth operation of the valve.

An enlarged view illustrating the position of the transverse shoulderunder the several conditions imposed in operation is shown more clearlyin FIG. 6, with the identifying data for the conditions adjacentthereto. The respective conditions illustrated are theoretical, in thatthey do not take into consideration the rolling and stretching actionaccommodated by the web 36 and frusto-conical portion 37, which join thesinusoidal shoulder portion 33 to the base 31 and nipple portion 32,respectively. It is to be emphasized that the action referred to aboveserves two basic functions in that it reduces the localization offlexure, i.e., the web 36 and frusto-conical portion 37, because oftheir relatively thin design, will flex along with the transverseshoulder portion 33. Secondly, during the travel of the stem slightrolling will occur at these relieved portions, which will reduce theoverall amount of flexure necessary to accommodate stem travel. However,such action, while exceedingly favorable in securing optimum results inoperation, is difiicult to illustrate on a theoretical basis, so theidentifying data of FIG. 6 does not comprehensively treat the rollingand flexing action experienced by the web 36 and frusto-conical portion37, during actual operation.

The respective dimensions of travel are by way of example only, for acommercial embodiment. However, it is felt that the relationshipexpressed by the dimension will hold generally true, regardless of theparticular size, i.e., the downward flexing of the seat cup equallingabout one-third of the total axial travel of the stem ignoring rollingat the web 36 and frusto-conical portion 37. Thus, in opening, the sternwill travel through the free state on about the first third of openingmovement, and as it continues to full open, the seat cup will flex androll at the transverse shoulder portion to compensate for the amount ofstem travel. At full open, the shoulder is flexed at its maximum atdistance beyond the free state of about two-thirds the stern travel.

The phantom lines indicate the respective positions of the web 36 andfrusto-conical portion 37 at the closed and open positions; Oninspection of the embodiment, by those skilled in the art, it isapparent that the relieved portions serve the important functions notedabove. This will become more clearly apparent on comparison with a priorart model hereinafter.

The above theoretical relationship of the movement of the transverseshoulder may be thus represented by mathematical approximation. Thegreatest distance the shoulder portion moves with respect to its freestate position is approximately equal to two-thirds the total travel ofthe stem, or

where E is the greatest distance the shoulder portion moves beyond itsfree state position when the valve is open, and r is the totalreciprocal movement of the stem from valve open to valve closedposition.

A further expression is available to define the relationship at closingwhich is arbitrarily represented by E It has been found that E isapproximately equal to the maximum travel of the stem divided by 3. Inequation form where E is the greatest distance the shoulder portionmoves beyond its free state position when the valve is closed, and r isthe total reciprocal movement of the stem from valve open to valveclosed position.

From this relationship it is obvious that the relationship could beredefined with the integers being replaced by algebraic representationsof constants. In equation form Eo= and E,,=L a b where a and 11represent constants. This relationship thus could lead one to flexingthe transverse shoulder portion an equal amount in the two positions,opened and closed, with the intermediate position being the free orunflexed state.

However, in practice, the valve remains in the closed position forsubstantially longer periods; therefore, it is advantageous tounderstress the transverse shoulder in the closed postion with respectto the full open positiongin order to maximize the life of the seat cup.It is felt that the most satisfactory relationship of the limits will bedictated by the environment and conditions of the anticipated use.

In one concrete embodiment, as shown in FIG. 8, the free end 511 of thenipple portion, if inserted into the seal chamber, without stressing inthe area of the transverse shoulder, would be approximately about inchoff the seat 15, or d would be equal to about inch. Upon insertion ofthe stem, and in the closed position, as shown in FIG. .9, the free endof the nipple portion would be forced against the valve seat 15 with asealing force which may be adjusted slightly, by merely rotating the capassembly 20. It can be appreciated that, upon raising the stem the firstinch of travel, such action brings the seat cup back to the free statewherein the transverse wall portion is generally sinusoidal, as shown inthe solid lines of FIG. 6. Continuing to full open, the transverse wallportion assumes substantially a sinusoidal construction; however, theamplitude is increased by approximately two-thirds the amplitude of thatin the free state. It thus can be seen that the maximum overall flexurehas been reduced by about onethird that occasioned with respect to theprior art devices.

The nutation which occurs in the first one-third of stem travel does notserve to overstress the transverse wall portion, .since,.during suchtravel, the wall portion is transcending from a slightly flexed state toa no flexed state. Thus, any flexure induced by nutation of the stemwill be accommodated by a slight flexing and rolling in the plane ofmutation with no adverse effect on the transverse wall portion. Theadvantages of the instant device Will become more evident when the priorart is discussed below.

Referring now to FIGS. 10 through 12, herein is disclosed a prior artmodel in a valve arrangement similar to the instant invention. Forconvenience of comparison, reference characters identical to thereference characters of FIG. 1 with a prime attached will be used toidentify corresponding elements.

The valve 10 comprises a body 11-, an outlet '12 and an inlet 13'.Transversely of the outlet 12' is a seat 15. A passage 14' joins theoutlet 12' to the inlet 13. The valve body 11' houses the passage 14'which is comprised of cylindrical portion 16', frusto-conical portion17', and counterbored portion .98. Suitable thread means 19' is providedon the exterior of the body threadably to receive the cap assembly 20.The cap assembly is similarto the .cap assembly shown in the embodimentof FIG. 1 in that it comprises a bonnet 21', handle means 93, stem means23, having a collar 24' at the lower extremity, reduced cylindricalportion 28, and a knob 27' at the terminus .point of. the stem. The seatcup 30 is comprised of a nipple portion 32' joined by a flexible Webportion 37', which merges into a transverse shoulder.

33', thence into base portion 31'. The base portion is generallycylindrical in configuration, terminating in radially extending shoulder33', which turns arcuately into the web portion 37 and is connected tothe nipple portion 32'. The nipple portion is provided with a knob--receiving aperture 44' and cylindrical portion 42 to receive thecomplementary parts on the stern, shown fragmentarily thereabove. Theseat cup is inserted into the passageway 14' until the nipple portion32' engages the seat portion 1-5. The radial shoulder 33' engages thecounterbored portion 98' on the shoulder thereby limiting the depth towhich the base portion 31' may be inserted. The seat cup is snapped overthe stem in the same manner as the instant device that is, the knob isforced through the reduced cylindrical portion 42' into the knobreceiving aperture 44' so that the nipple portion grips the knob 27' soas to travel therewith.

The bonnet, having expander 50' with frusto-conical surface 52' andcylindrical surface 51', is threadedly received on the body, portion, asis best seen in FIG. 12.

The base portion 31 is thereby clampingly received between the shoulder90 and the bonnet, thereby increasing its radial thickness when the cap21' is threadably attached to the body portion 13'. When the stem israised, as shown in phantom lines in FIG. 12, the seat cup assumes, atthe radial shoulder, a configuration shown in phantom lines at 91'. Fromthis configuration it can be seen that the maximum stretching of theshoulder must be equal to the length of the stem travel, or, forexample, if the stem travel is inch, the seat cup must stretch & inch,folding as indicated at 91. Such yield approaches the elastic limit byapproximately one-third more than would be true with respect to theinstant embodiment ignoring the rolling action thereof, thus causing ashorter fatigue life than in the present case. However, it must be bornein mind that with respect to elastomeric materials, such as the siliconrubber which has found satisfactory use in commercial embodiments,stress is not directly proportional to strain. The stress-strain curvefor rubber on retraction does not follow the same course as during theextension but forms a hysteresis loop. On successive extensions andretractions, the areas of the successive loops diminish to a minimum,thus showing a corresponding decrease in hysteresis.

Referring now to FIG. 13, therein is shown a graphical representation ofthe stem lift in inches versus the seat cup strain in percent, with thecurves representing the prior art and instant invention. The stem liftis indicated in inches along the Y axis, the normal stem travel beingabout A inch. The seat cup strain in percent is referenced to the priorart device shown, the prior art device having 100 percent strain at fullstem travel. It can be seen, again ignoring rolling, that the novelembodiment employing the improved seat cup, which is preflexed, willhave in the closed position slightly in excess of 30 percent strainthereon. As the stern lifts at inch the strain is theoretically zero,and through the next inch, the strain rises to about 65 percent. Theprior art device starts, in the closed position, with zero strain.However, for the inch travel, it "increases up to 100 percent. Thiscomparative graph shows that, with respect to prior art devices,approximately one-third less strain is experienced by the instant seatcup design at full open, and under equivalent conditions. Suchdifference is of substantial magnitude and gives rise ultimately to amuch longer seal life. In the comparative analysis depicted by FIG. 13,it has been assumed that the instant embodiment will be subjected topure strain to accommodate stem travel. However, as heretofore noted,the relieving of the base member permits slight rolling, and furtherminimizes strain or stretching. Thus, in actual practice the seat cupstrain will be substantially less than 66 percent of that of the priorart, which has its base portion fixedly held so the transverse shouldermust yield to accommodate all movement.

FIG. 14 is a theoretical representation of the imposed extensions inpercent versus the number of cycles to break. For example, if a one inchelastomer were extended to 1% inches, or 25 percent of its total length,it would require cycles to cause failure of such elastomer. It will beappreciated that the prior art device described previously requires, incomparison to the cup of this invention, on the order of inch moremaximum extension on each cycle of operation. In practice this wouldamount to about one-third increase in the percentage of fiexure. Sincethe curve approaches the X axis asymptotically, slight variations in thelower percentage ranges will materially increase or decrease the numberof cycles to break. For example, in one concrete embadiment the percentof elongation was lowered from about to about 10 percent. Thistheoretically would increase the expected life of the instant device byabout 10 times. For purposes of this discussion, the rolling of thetransverse shoulder portion has again been omitted; however, it isimportant to note that the rolling action will serve to reduce the per-10 centage of elongation while kneading the rubber to keep it soft andpliable over the years.

The curve shown in dotted lines on FIG. 14 is included to showtheoretically the influence of an incomplete relaxation on an elastomer.It is emphasized that this beneficial effect is not amenable totheoretical treatment at this time, such data being derivedexperimentally. It is only possible to estimate a lower limit forfatigue life when the rubber is not relaxed to zero strain on eachcycle. It is felt that this beneficial effect is achieved in the instantdevice by having the seat cup under stress in both the open and closedpositions. A complete relaxation will not be had, since the elasticproperties will lag the stem travel on opening. It is thought that thezero strain condition will merely be passed through on each cycleWithout allowing a complete relaxation of the elastomer.

The theoretical treatment of the device has been added in an attempt toeffect a complete understanding of the operation and advantages of theinstant invention. Although various dimensions and concrete exampleshave been used, it is not intended that this be limiting since such hasbeen done in the interest of ease and completeness of description. It isintended that the scope of the invention be defined by the spirit andscope of the appended claims.

I claim:

1. A valve for controlling fluid flow and including:

a valve body having inlet and outlet ports,

a fluid passageway in the valve body interconnecting said ports.

a seal chamber intermediate the ends of the passagea sealing seatdefined by the seal chamber transverse the axis of the passageway,

resilient sealing means disposed in the seal chamber,

an elongated tubular base portion included as a part of the sealingmeans and aligned with the seat, an elongated tubular nipple portionincluded as a part of the sealing means and of smaller cross-sectionaldimension than the base portion, the nipple being generally coaxial withthe base and extending therefrom toward the seat, means mounting thebase portion in the valve body against substantial axial and lateralmovement,

means for reciprocating the nipple portion into and out of fluid sealingengagement with the seat, and a transversely extending shoulder portionjoining the nipple portion to the base portion, the shoulder portionbeing, in the free state, offset toward the base portion in the zone ofsuch shoulder next adjacent the nipple; the shoulder, when the valve isclosed, being flexed somewhat beyond its free state position in thedirection of the seat, and when the valve is full open, being flexedsomewhat beyond its free state position in the direction away from theseat.

2. The valve of claim 1 wherein said means mounting the base portion inthe valve body includes a bonnet adjustably attached to said body, saidbonnet having a locator portion depending from the under side thereofwith an outer peripheral portion extending into said bonnet to form oneside of a groove, the other side of said groove being substantiallycoextensive with an adjacent inner peripheral portion of said body.

3. A valve for controlling fluid flow and including:

a valve body having inlet and outlet ports,

a fluid passageway in the valve body interconnecting said ports,

a seal chamber intermediate the ends of the passagea sealing seatdefined by the seal chamber transverse the axis of the passageway,

a stem in the seal chamber having one end opposed to the sealing seat ingenerally aligned relationship therewith,

. resilient sealing means disposed in the seal chamber and received oversaid one end portion of the stem, an elongated tubular base portionincluded as a part of the sealing means and aligned with the seat,

r is the total reciprocal movement of the stem from valve open to valveclosed position. 6. A valve for controlling fluid flow and including: avalve body having inlet and outlet ports,

an elongated tubular nipple portion included as a part a fluidpassageway in the valve body interconnectof the sealing means, and ofsmaller cross-sectional ing said ports, dimension than the base portion,the nipple being a seal chamber intermediate the ends of thepassagegenerally coaxial with the base and extending thereway, fromtoward the seat, a sealing seat defined by the seal chamber transversemeans mounting the base portion in the valve body the axis of thepassageway,

against substantial axial and lateral movement, a stern in the sealchamber having one end opposed means to reciprocate the stem toward andaway from to the sealing seat in generally aligned relationship thesealing seat, therewith, means mounting the nipple portion to said endportion resilient sealing means disposed in the seal chamber of the stemfor reciprocation with the stem into and 15 and received over said oneend portion of the stern, out of fluid sealing engagement with the seat,and an elongated tubular base'portion included as a part a transverselyextending shoulder portion joining of the sealing means and aligned withthe seat, the nipple portion to the base portion, the shoulder anelongated tubular nipple portion included as a part portion, when thevalve is closed, being disposed of the sealing means and of smallercross-sectional beyond its free state position in the direction of thedimension than the base portion, the nipple being seat, and when thevalve is open, being disposed generally coaxial with the base andextending therebeyond its free state position in the direction away fromtoward the seat, from the seat. means mounting the base portion in thevalve body A. The valve of claim 3 wherein said means mounting againstsubstantial axial and lateral movement, the base portion in the valvebody includes a bonnet means to reciprocate the stem toward and awayfrom adjustably attached to said body, said bonnet having a the sealingseat, relieved groove portion on the under side thereof, one meansmounting the nipple portion to said end portion side of said groovebeing substantially coextensive with an of the stem for reciprocationwith the stem into inner peripheral portion of said body, said bonnetand and out of fluid sealing engagement with the seat, said bodygripping by engaging said tubular base portion. and

transversely extending shoulder portion joining the base portion to thenipple portion, said shoulder obeying the following relations:

5. A valve for controlling fluid flow and including: a a valve bodyhaving inlet and outlet ports, a fluid passageway in the valve bodyinterconnecting said ports, a seal chamber intermediate the ends of thepassage- (a) E 1 w y, a a sealing seat defined by the seal chambertransverse the axis of the passageway, (b) E 1 a stern in the sealchamber having one end opposed to c 5 Edge seatlliang seat in generallyaligned relationship 40 where erewi resilient sealing means disposed inthe seal chamber 18 the greatest. dlstance the shpillder Demon andreceived over Said one end portion of the Stem, moves beyond its freestate position when the an elongated tubular base portion included as apart B t i open t th h 1d of the sealing means and aligned with theseat, c 15 e greates. lstance e S 3 er portlon an elongated tubularnipple portion included as a part 49 moves. beyond Its .free stateposmon when the of the sealing means and of smaller cross-sectionalValve 15 closed dimension than the base portion, the nipple being azindbare constartts and generally coaxial with the base and extending thererg gifz l gg lg g gz igzg 1 2E323 Stem from toward the Seat 50 7. Thevalve of claim 6 wherein the constants a and means mounting the baseportion in the valve body against substantial axial and lateralmovement,

means to reciprocate the stem toward and away from the sealing seat,

means mounting the nipple portion to said end portion of the stem forreciprocation with the stem into and out of fluid sealing engagementwith the seat, and

a transversely extending shoulder portion joining the base portion tothe nipple portion, said shoulder b are in the relationship of b a 1.

8. The valve of claim 6 wherein said means mounting the base portion inthe valve body includes a bonnet adjustably attached to said body, saidbonnet having a locator portion depending from the under side thereofwith an outer peripheral portion extending into said bonnetto form oneside of a groove, the other side of said groove being substantiallycoextensive with an adjacent inner peripheral portion of said body.

a 9. A valve for controlling fluid flow and including: obeylng thefollowmg relations a valve body having inlet and outlet ports,

2T a fluid passageway in the valve body' interconnecting E g said ports,

3 a seal chamber intermediate the ends of the passage- T W y (b) E asealing seat defined by the seal chamber transverse the axis of thepassageway, Wher a stern in the seal chamber having one end opposed E isthe greatest distance the shoulder portion ig igs ifif seat In generallyaligned relatlonshlp moves. beyond Its 't State Positlon when theresilient sealing means disposed in the seal chamber Valve 15 p andreceived over said one end portion of the stem, EC is the greatestdistance the shoulder Portion an elongated tubular base portion includedas a part moves beyond its free state position when the of the sealingmeans and aligned with the seat, valve is closed, and an elongatedtubular nipple portion included as a part of the sealing means and ofsmaller cross-sectional dimension than the base portion, the nipplebeing generally coaxial with the base and extending therefrom toward theseat,

means mounting the base portion in the valve body against substantialaxial and lateral movement,

means to reciprocate the stem toward and away from the sealing seat,

means mounting the nipple portion to said end portion of the stem forreciprocation with the stem into and out of fluid sealing engagementwith the seat,

a transversely extending shoulder portion joining the base portion andthe nipple portion, the shoulder having a free state position,

the arrangement and dimensional interrelationship between said sealingmeans and said valve causing the shoulder, when the valve is closed, tobe distorted an appreciable distance beyond its free state position andin the direction toward the sealing seat, and

said arrangement and dimensional interrelationship also causing theshoulder, when the valve is open, to be distorted an appreciabledistance beyond its free state position and in the direction away fromthe sealing seat.

10. A valve as described in claim 9 characterized in that the lastmentioned distance is greater than the first.

11. A valve for controlling fluid flow and including:

a valve body having inlet and outlet ports,

a fluid passageway in the valve body interconnecting said ports,

a seal chamber intermediate the ends of the passagea sealing seatdefined by the seal chamber transverse the axis of the passageway,

resilient sealing means disposed in the seal chambers,

an elongated tubular base portion included as a part of the sealingmeans and aligned with the seat,

an elongated tubular nipple portion included as a part of the sealingmeans and of smaller cross-sectional dimension than the base portion,the nipple being generally coaxial with the base and extending therefrom toward the seat,

means mounting the base portion in the valve body against substantialaxial and lateral movement,

means for reciprocating the nipple portion into and out of fluid sealingengagement with the seat,

a transversely extending shoulder portion joining the base portion andthe nipple portion, the shoulder portion having a free state position,and

the arrangement and dimensional interrelationship between said sealingmeans and said valve causing the total displacement of the shoulderportion beyond its free state position, during opening and closing ofthe valve, to be less than the total reciprocal travel of the stem.

12. A valve as described in claim 11 characterized by the following:

a peripheral zone of increased wall thickness at the free end portion ofthe tubular base portion, and

expander means within the free end portion of the tubular base portionfor forcing said zone tightly against the wall of the sealing chamber.

13. A valve as described in claim 12 in which a portion of said zone isformed by an external locator ridge for positioning the sealingmeanswithin the seal chamber.

14. The valve of claim 13 wherein said means mounting the base portionin the valve body includes a bonnet adjustably attached to said body,said bonnet having a locator portion depending from the under sidethereof with an outer peripheral portion extending into said bonnet toform one side of the groove, the other side of said groove beingsubstantially coextensive with an adjacent inner peripheral portion ofsaid body.

15. The valve of claim 11 wherein said means mounting the base portionin said valve body includes a bonnet 14 adjustably attached to saidbody, said bonnet having a locator portion depending from the under sidethereof with an outer peripheral portion extending into said bonnet toform one side of a groove, the other side of said groove beingsubstantially coextensive with an adjacent inner peripheral portion ofsaid body.

16. The valve of claim 11 wherein said means for re ciprocating thenipple portion comprises a stem in the seal chamber having one endopposed to the sealing seat and in generally aligned relationshiptherewith,

means to reciprocate the stem toward and away from the sealing seat,

and means mounting the nipple portion to the end portion of said stemfor reciprocation with said stem.

17. A valve for controlling fluid flow and including:

a valve body having inlet and outlet ports,

a fluid passageway in the valve body interconnecting said ports,

a seal chamber intermediate the ends of the passageway,

a sealing seat defined by the seal chamber transverse the axis ofthepassageway,

a stem in the seal chamber having one end opposed to the sealing seat ingenerally aligned relationship therewith,

resilient sealing means disposed in the seal chamber and received oversaid one end portion of the stem,

an elongated tubular base portion included as a part of the sealingmeans and aligned with the seat,

an elongated tubular nipple portion included as a part of the sealingmeans and of smaller cross-sectional dimension than the base portion,the nipple being generally coaxial with the base and extending therefromtoward the seat,

means mounting the base portion in the valve body against substantialaxial and lateral movement,

means to reciprocate the stem toward and away from the sealing seat,

means mounting the nipple portion to said end portion of the stem forreciprocation with the stem into and out of fluid sealing engagementwith the seat,

a transversely extending shoulder portion joining the base portion andthe nipple portion, the shoulder portion having a free state position,

the arrangement and dimensional interrelationship between said sealingmeans and said valve causing the total displacement of the shoulderportion beyond its free state position, during opening and closing ofthe valve, to be less than the total reciprocal travel of the stem,

a peripheral zone of increased wall thickness at the free end portion ofthe tubular base portion, a part of the peripheral zone being formed byan external locator ridge for positioning the sealing means within theseal chamber, and

a second zone being provided of reduced wall thickness relative to theremainder of the sealing means, the second zone including as a partthereof the transverse shoulder portion and those sections of thetubular base and nipple portions, respectively, next adjacent thetransverse shoulder portion.

18. A valve for controlling fluid flow and including:

a valve body having inlet and outlet ports,

a fluid passageway in the valve body interconnecting said ports,

a seal chamber intermediate the ends of the passagea sealing seatdefined by the seal chamber transverse the axis of the passageway,

resilient sealing means disposed in the seal chamber,

a base portion included as a part of the sealing means,

an elongated tubular nipple portion included as a part of the sealingmeans with the nipple portion being generally coaxial with and extendingtoward the sealing seat,

means mounting the base portion in the valve body against substantialaxial and lateral movement,

means for reciprocating the nipple portion into and out of fluid sealingengagement with the sealing seat,

and a transversely extending shoulder portion joining the nipple portionto the base, the shoulder portion being, in the free state, offsettoward the base portion in the zone of such shoulder next adjacent thenipple; the shoulder, when the valve is closed, being flexed somewhatbeyond its free state position in the direction of the seat, and whenthe valve is full open, being flexed somewhat beyond its free stateposition in the direction away from the seat.

References Cited by the Examiner UNITED STATES PATENTS ISADOR WEIL P mqEx m n

1. A VALVE FOR CONTROLLING FLUID AND INCLUDING: A VALVE BODY HAVINGINLET AND OUTLET PORTS, A FLUID PASSAGEWAY IN THE VALVE BODYINTERCONNECTING SAID PORTS. A SEAL CHAMBER INTERMEDIATE THE ENDS OF THEPASSAGEWAY, A SEALING SEAT DEFINED BY THE SEAL CHAMBER TRANSVERSE THEAXIS OF THE PASSAGEWAY, RESILIENT SEALING MEANS DISPOSED IN THE SEALCHAMBER, AN ELONGATED TUBULAR BASE PORTION INCLUDED AS A PART OF THESEALING MEANS AND ALIGNED WITH THE SEAT, AN ELONGATED TUBULAR NIPPLEPORTION INCLUDED AS A PART OF THE SEALING MEANS AND OF SMALLERCROSS-SECTIONAL DIMENSION THAN THE BASE PORTION, THE NIPPLE BEINGGENERALLY COAXIAL WITH THE BASE AND EXTENDING THEREFROM TOWARD THE SEAT,MEANS MOUNTING THE BASE PORTION IN THE VALVE BODY AGAINST SUBSTANTIALAXIAL AND LATERAL MOVEMENT, MEANS FOR RECIPROCATING THE NIPPLE PORTIONINTO AND OUT OF FLUID SEALING ENGAGEMENT WITH THE SEAT, AND